Hiring a GXT developer can significantly enhance your web application development. They are skilled in using Google Web Toolkit (GWT), a powerful tool for creating rich user interfaces. GXT developers can develop complex, high-performance applications that are easy to maintain, scalable, and cross-browser compatible. They also have the ability to create customizable themes and widgets, making your application visually appealing. Their expertise will ensure your application is robust, user-friendly, and responsive, thus enhancing user satisfaction and potentially increasing your business productivity and revenue.